Statistics pls help: How r the p-value, the null hypothesis and the test of statistical significance related?

Question

I am doing this home work in stats and I need somebody's help. Thank you very much for anybody who can answer this question fast.

Answer 1

Here's how it works. You want to test if there is an effect to something, say whether a medicine works.

The null hypothesis *assumes that the medicine does not work. (The alternative hypothesis would then be that it does). When you perform a significance test, you will get a p-value. Let me explain p-values like this:

You know a coin comes up heads half the time; however, you would not be surprised if you flipped a coin 10 times and only got 4 heads. This is obviously due to some slight random chance.
But how do we determine what is random chance and what is a real effect? With a p-value. The p-value tells us the probability that an event occurred solely due to random chance.

If you are testing the medicine and you get a p-value of 0.333, that says that, if the medicine isn't working, you'll get those results 1 in 3 times, just by chance. But if the p-value is 0.001, that says that the results that you got are SO extreme, they would only occur 1 in 1000 times by chance. Here, it seems likely that the medicine is having a significant effect.

Generally, 0.05 is considered a rough mark for whether or not some result is due to chance.